CN113319113A - Thermal desorption device and process for organic contaminated soil - Google Patents
Thermal desorption device and process for organic contaminated soil Download PDFInfo
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- CN113319113A CN113319113A CN202110532302.3A CN202110532302A CN113319113A CN 113319113 A CN113319113 A CN 113319113A CN 202110532302 A CN202110532302 A CN 202110532302A CN 113319113 A CN113319113 A CN 113319113A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/06—Reclamation of contaminated soil thermally
Abstract
The invention belongs to the technical field of soil ex-situ remediation, and particularly relates to a thermal desorption device and process for organic contaminated soil, which solve the problems that in the prior art, the operation steps are complicated, the energy consumption is high, the heat in a thermal desorption cavity cannot be fully utilized, and the waste heat utilization efficiency is low. The device comprises a thermal desorption system for reducing energy consumption in the thermal desorption process, a metering and feeding system, a soil body heat exchange unit and a tail gas purification system; the thermal desorption system comprises a thermal desorption cavity and a combustion chamber, and the thermal desorption system simultaneously burns the thermal desorption of the organic polluted soil and the waste generated by the thermal desorption; the soil material inlet of the thermal desorption cavity is connected with the metering feeding system, the soil material outlet of the thermal desorption cavity is connected with the soil body heat exchange unit, and the soil material inlet of the thermal desorption cavity is connected with a tail gas purification system for purifying tail gas generated by thermal desorption. The invention shortens the process, reduces the process period and the process cost, realizes the high-efficiency treatment of thermal desorption, greatly reduces the energy consumption, and can fully utilize the waste heat.
Description
Technical Field
The invention belongs to the technical field of soil ex-situ remediation, and particularly relates to a thermal desorption device and process for organic contaminated soil.
Background
With the adjustment of the industrial structure of the city, a large number of industrial sites need to change the land utilization mode. Governments all provide that industries with high pollution, high energy consumption and resource types can be guided to comprehensively exit central urban areas, and scattered industrial enterprises in the central urban areas are promoted to move and gather to gardens. While the problem of relocation of heavily polluted industrial enterprises is solved, site pollution of the relocated and closed industrial enterprises has attracted high attention of relevant departments due to accumulation and high risk. In order to avoid the harm of the polluted site to the health of human bodies and the ecological environment, a large amount of soil remediation and treatment work of the polluted site is pursued at the very beginning.
The thermal desorption technology is a heating treatment technology capable of efficiently removing pollutants in soil, and is a process for heating a polluted medium and pollutants contained in the polluted medium to a sufficient temperature through direct or indirect heat exchange so as to enable the pollutants to be exerted or separated from the polluted medium, so that various volatile or semi-volatile organic pollutants in a polluted site can be efficiently removed, and the removal rate of the pollutants can reach more than 99.98%. The thermal desorption device has the advantages of simple process, mature technology and the like, but the thermal desorption device has a complex structure, higher construction cost, high operating cost, inconvenient operation and operation, huge energy consumption, incapability of fully utilizing waste heat and certain requirements on the particle size and the water content of treated soil.
The invention patent 201810987522.3 discloses a method for treating thermal desorption tail gas of organic contaminated soil, which is used for carrying out dust removal pretreatment on high-temperature tail gas generated by the thermal desorption treatment of the organic contaminated soil; introducing the dedusted thermal desorption tail gas into a heat accumulating type heat exchange device, and carrying out oxidation reaction on organic pollutants and oxygen in a high-temperature environment to generate carbon dioxide and water so as to realize high-temperature thermal decomposition of organic matters; the treated flue gas is introduced into an iron-making blast furnace, and the residual organic pollutants in the flue gas are thoroughly decomposed by using the ultrahigh temperature and the oxidation-reduction atmosphere of the iron-making blast furnace. The invention can fully utilize production facilities and energy sources in metallurgical industries such as steel and the like, and realize the complete decomposition of organic pollutants in the thermal desorption tail gas of the soil. However, the utilization of the waste heat is limited and cannot be widely popularized and utilized.
The invention patent 201810554641.X discloses a device for repairing organic polluted soil by indirect thermal desorption with high-efficiency energy level gradient utilization. By integrating and utilizing the waste heat of each gas phase link in the indirect thermal desorption process, the energy of the whole system is efficiently and gradiently utilized. Meanwhile, the pollutant removal effect is improved through processes such as condensation, three-phase separation, water treatment, mud treatment, activated carbon adsorption and the like, and byproducts can be effectively prevented from being produced and secondary pollution can be effectively avoided. However, the separate treatment of the thermal desorption and the incineration of the organic pollution waste gas has huge energy consumption, and the steps are complicated in the waste heat utilization process.
It can be seen that the existing thermal desorption devices respectively treat soil thermal desorption and organic pollutants desorbed from the thermal desorption devices, so that the operation steps are complicated, the energy consumption is high, the heat in a thermal desorption cavity cannot be fully utilized, and meanwhile, the effective utilization of waste heat is lacked.
Disclosure of Invention
The invention provides a thermal desorption device and a thermal desorption process for organic polluted soil, and aims to solve a series of problems that in the prior art, the energy consumption is huge, the heat in a thermal desorption cavity cannot be fully utilized, the energy consumption is high, the waste heat utilization efficiency is low, and the like.
The invention is realized by adopting the following technical scheme: a thermal desorption device for organic contaminated soil comprises a thermal desorption system, a metering feeding system, a soil body heat exchange unit and a tail gas purification system, wherein the thermal desorption system is used for reducing energy consumption in a thermal desorption process;
the thermal desorption system comprises a thermal desorption cavity and a combustion chamber, a channel for connecting the thermal desorption cavity and the combustion chamber is arranged between the thermal desorption cavity and the combustion chamber, and the thermal desorption system simultaneously burns wastes generated by thermal desorption and thermal desorption of the organic polluted soil;
be equipped with thermal desorption chamber soil material entry on the thermal desorption system, thermal desorption chamber soil material export and combustion chamber exhanst gas outlet, thermal desorption chamber soil material entry links to each other with measurement charge-in system, thermal desorption chamber soil material export links to each other with soil body heat transfer unit, the hot-air that soil body heat transfer unit produced lets in the combustion chamber, soil body heat transfer unit provides fuel and heat for thermal desorption system when to the cooling of the soil body after the thermal desorption, thermal desorption chamber soil material entry links to each other with the tail gas clean-up system to the tail gas clean-up that the thermal desorption produced.
Furthermore, a thermal desorption cavity of the thermal desorption system is of a cylindrical structure, an inner cavity is arranged inside the thermal desorption cavity, an auger is arranged inside the inner cavity, a thermal desorption cavity soil outlet communicated with the inner cavity and a thermal desorption cavity gas outlet communicated with the inner cavity are formed in the thermal desorption cavity, the thermal desorption cavity soil outlet is communicated with the soil body heat exchange unit, a cavity for hot air circulation is formed in a wall body of the thermal desorption cavity, the cavity is isolated from the inner cavity, and a dust exhaust port communicated to the outside and used for exhausting dust particles out of the cavity is formed in the cavity;
the combustor is provided with a combustor, the bottom of the combustor is provided with a channel and an organic polluted waste gas inlet, the channel communicates the combustor with the cavity, the organic polluted waste gas inlet is communicated with a gas outlet of the thermal desorption cavity through a pipeline, the pipeline is provided with a draught fan, the combustor is further provided with a flue gas outlet of the combustor and a waste heat recovery hot air inlet, the flue gas outlet of the combustor is communicated with a tail gas purification system, and the waste heat recovery hot air inlet is communicated with a soil body heat exchange unit.
Furthermore, the wall body of combustion chamber includes inner wall and outer wall, is equipped with the intermediate layer between inner wall and the outer wall, is equipped with a plurality of aperture on the inner wall, intermediate layer and passageway intercommunication.
Furthermore, the number of the burners of the combustion chamber of the thermal desorption system is two, namely a burner I and a burner II, and the two burners are arranged diagonally;
the number of the channels is two, namely a gas channel I and a gas channel II;
one for each burner.
Furthermore, the inner wall of the cavity is made of high-temperature-resistant heat conduction materials, and the outer wall of the cavity is made of high-temperature-resistant heat insulation materials.
Further, be equipped with air-blower I and air-blower II on the soil body heat transfer unit, the top of soil body heat transfer unit is equipped with pan feeding mouth and refrigerated soil export, and the pan feeding mouth links to each other with the export of heat desorption chamber soil material, and refrigerated soil exit linkage has and is used for cooling out the band conveyer of soil and link to each other, and the bottom of soil body heat transfer unit is connected with soil body heat transfer unit blast pipe, and soil body heat transfer unit blast pipe links to each other with waste heat recovery hot-air inlet, is equipped with the draught fan on the soil body heat transfer unit blast pipe.
Further, the tail gas purification system comprises a cyclone dust collector, a bag-type dust collector, a spray cooling tower and an active carbon adsorption device which are connected in sequence;
the top of the cyclone dust collector is provided with an air inlet pipe and an air outlet pipe, the bottom of the cyclone dust collector is provided with an ash bucket, and the outlet end of the ash bucket is provided with a star-shaped blanking valve;
the bag-type dust collector is provided with a bag-type dust collector flue gas inlet and a bag-type dust collector flue gas outlet;
the activated carbon adsorption device is provided with an activated carbon adsorption device flue gas inlet and an activated carbon adsorption device flue gas outlet, and the activated carbon adsorption device flue gas outlet is provided with a centrifugal fan;
the air inlet pipe of the cyclone dust collector is connected with the flue gas outlet of the combustion chamber, the exhaust pipe is connected with the flue gas inlet of the bag-type dust collector, and the flue gas outlet of the bag-type dust collector is connected with the flue gas inlet of the activated carbon adsorption device through the spray cooling tower.
Further, a temperature sensor and a pressure sensor are arranged at the tail part of the thermal desorption cavity of the thermal desorption system; the top of the combustion chamber is provided with a temperature sensor and a pressure sensor.
The thermal desorption process of the organic polluted soil comprises the steps that the organic polluted soil is subjected to indirect thermal desorption in a thermal desorption system, the organic polluted soil in the thermal desorption system is heated for thermal desorption under the condition of not contacting high-temperature gas by utilizing the heat conduction of metal in the indirect thermal desorption process, secondary burning is carried out on waste generated by thermal desorption during the thermal desorption, and then primary dust removal treatment is carried out on dust particles generated by burning by utilizing airflow formed by burners arranged in an oblique diagonal direction; the soil body after thermal desorption is directly discharged after being cooled by the soil body heat exchange unit, and waste heat generated in the heat exchange process of the soil body heat exchange unit is recycled into the thermal desorption system, so that fuel and heat are provided for the thermal desorption system, and high-efficiency utilization of the heat is realized; and finally, further dedusting, cooling and adsorbing the flue gas subjected to thermal desorption.
Further, before the organic contaminated soil is subjected to thermal desorption, the organic contaminated soil is pretreated, the soil moisture is adjusted through the pretreatment, and the particle size of the soil is controlled to be a proper size.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the heat desorption device, the combustion chamber and the heat desorption cavity are arranged together and are communicated with each other through the channel, so that hot air generated by combustion of the combustion chamber is introduced into the heat desorption cavity, the heat desorption cavity is heated through heat conduction of metal to carry out heat desorption, waste gas generated by heat desorption enters the combustion chamber through the guide of the draught fan to be subjected to secondary ignition, and heat generated by ignition is input into the heat desorption cavity again, so that the heat desorption and the waste gas generated by heat desorption are simultaneously combusted and utilized, and the heat generated by burning of the waste gas is used for heat desorption, so that energy generated by a combustor is utilized extremely high, and energy consumption is greatly reduced;
2. the soil body heat exchange unit arranged in the device effectively reduces the soil temperature by utilizing cold air, and high-temperature hot air is introduced into the combustor to provide fuel and heat for the combustion of the combustor, so that the waste heat of the soil is efficiently utilized, and the energy consumption of the combustion chamber is saved;
3. the combustion chamber of the device is provided with two diagonally arranged burners, and gas in the burners forms anticlockwise rotating gas flow under the guidance of high-temperature gas flow sprayed by the two diagonally arranged burners, so that the contact area of organic polluted waste gas and flame is increased, and the burning efficiency is greatly improved;
4. the combustion chamber of the device is provided with an interlayer, the inner wall of the interlayer is provided with small holes, a plurality of dust particles are mixed in the organic polluted waste gas and the hot air of the soil body heat exchange unit after thermal desorption, the dust particles move in the interlayer from the small holes under the action of centrifugal force, then enter the cavity from the channel, and then are discharged out of the thermal desorption system from the dust discharge port under the action of the baffle plate, so that the dust particles can be preliminarily removed, the loss of the device can be reduced, and the subsequent dust removal efficiency can be increased;
5. the process can simultaneously carry out thermal desorption and firing of organic polluted waste gas generated by thermal desorption, shortens the process, reduces the process period and the process cost, realizes high-efficiency treatment of thermal desorption, greatly reduces the energy consumption, and can fully utilize the waste heat; and the hot air after the heat exchange of the soil body heat exchange unit is supplied to thermal desorption to be used as fuel and heat, so that the high-efficiency utilization of the heat is realized.
Drawings
FIG. 1 is a schematic diagram of the present apparatus;
FIG. 2 is a schematic view of a combustion chamber;
FIG. 3 is a schematic cross-sectional view of a combustion chamber;
FIG. 4 is a schematic diagram of a soil heat exchange unit;
FIG. 5 is a top view of a thermal desorption system;
FIG. 6 is a flow chart of the present process;
in the figure: 1-a storage bin, 2-a conveying belt, 3-a belt weigher, 4-a thermal desorption cavity soil material inlet, 5-a thermal desorption cavity, 5.1-an inner cavity, 5.2-a cavity, 6-an auger drill, 7-a combustion chamber, 8-a combustion chamber flue gas outlet, 9-a waste heat recovery hot air inlet, 10-a thermal desorption cavity soil material outlet, 11-an air inlet pipe, 12-an air outlet pipe, 13-an ash hopper, 14-a cyclone dust collector, 15-a bag dust collector, 16-a bag dust collector flue gas inlet, 17-a bag dust collector flue gas outlet, 18-a spray cooling tower, 19-an active carbon adsorption device flue gas inlet, 20-an active carbon adsorption device, 21-an active carbon adsorption device flue gas outlet, 22-a material inlet and 23-a blower I, 24-a blower II, 25-an induced draft fan, 26-a soil heat exchange unit exhaust pipe, 27-a soil outlet, 28-a soil heat exchange unit, 29-a combustor I, 30-a combustor II, 31-small holes, 32-an outer wall, 33-an inner wall, 34-a gas channel I, 35-a gas channel II, 36-a channel, 37-an organic pollution waste gas inlet, 38-a heat desorption cavity gas outlet, 39-a centrifugal fan, 40-a baffle, 41-a dust exhaust port and 42-a lateral support.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.
It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions under which the present invention can be implemented, so that the present invention has no technical significance, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.
Referring to fig. 1 to 6, the present invention provides a technical solution: a thermal desorption device for organic contaminated soil comprises a thermal desorption system, a metering and feeding system, a soil body heat exchange unit 28 and a tail gas purification system, wherein the thermal desorption system is used for reducing energy consumption in a thermal desorption process;
the thermal desorption system comprises a thermal desorption cavity 5 and a combustion chamber 7, a channel 36 for connecting the thermal desorption cavity 5 and the combustion chamber 7 is arranged between the thermal desorption cavity 5 and the combustion chamber 7, and the thermal desorption system simultaneously burns wastes generated by thermal desorption and thermal desorption of the organic polluted soil;
be equipped with thermal desorption chamber soil material entry 4 on the thermal desorption system, thermal desorption chamber soil material export 10 and combustion chamber exhanst gas outlet 8, thermal desorption chamber soil material entry 4 links to each other with measurement charge-in system, thermal desorption chamber soil material export 10 links to each other with soil body heat transfer unit 28, the hot-air that soil body heat transfer unit 28 produced lets in combustion chamber 7, soil body heat transfer unit 28 provides fuel and heat for the thermal desorption system when cooling to the soil body after the thermal desorption, thermal desorption chamber soil material entry 4 links to each other with the tail gas clean-up system to the tail gas clean-up that the thermal desorption produced.
The thermal desorption system is characterized in that a thermal desorption cavity 5 of the thermal desorption system is of a cylindrical structure, an inner cavity 5.1 is arranged in the thermal desorption cavity 5, an auger 6 is arranged in the inner cavity 5.1, a thermal desorption cavity soil outlet 10 communicated with the inner cavity 5.1 and a thermal desorption cavity gas outlet 38 communicated with the inner cavity 5.1 are formed in the thermal desorption cavity 5, the thermal desorption cavity soil outlet 10 is communicated with the soil body heat exchange unit 28, a cavity 5.2 for hot air circulation is formed in the wall body of the thermal desorption cavity 5, and the cavity 5.2 is isolated from the inner cavity 5.1 (the cavity 5.2 is used for storing hot air and transferring high temperature in a combustion chamber to the thermal desorption cavity, so that efficient utilization of energy is realized); a dust discharge port 41 communicated with the outside and used for discharging dust particles out of the cavity 5.2 is formed in the cavity 5.2, a baffle plate 40 is arranged in the cavity 5.2, and the baffle plate 40 is used for pushing the dust particles in the cavity 5.2 to be discharged from the dust discharge port 41 (mainly dust entering the thermal desorption cavity 5 through a channel after primary dust removal of the combustion chamber 7);
the combustion chamber 7 is provided with a combustor, the bottom of the combustor is provided with a channel 36 and an organic polluted waste gas inlet 37, the combustion chamber is communicated with the cavity 5.2 through the channel 36, the organic polluted waste gas inlet 37 is communicated with a heat desorption cavity gas outlet 38 through a pipeline, an induced draft fan is arranged on the pipeline, the combustion chamber 7 is also provided with a combustion chamber flue gas outlet 8 and a waste heat recovery hot air inlet 9, the combustion chamber flue gas outlet 8 is communicated with a tail gas purification system, and the waste heat recovery hot air inlet 9 is communicated with a soil body heat exchange unit 28; a lateral support 42 is arranged between the combustion chamber 7 and the heat desorption cavity 5, so that the connection between the combustion chamber 7 and the heat desorption cavity 5 is strengthened, and the stability of the combustion chamber 7 is ensured.
Thermal desorption system's thermal desorption chamber 5 be used for holding organic contaminated soil, the combustion chamber is used for burning the gas that thermal desorption produced and carry gas to thermal desorption chamber 5 and carry out thermal desorption through the heat exchange. The combustor further heats air by heating heat generated by natural gas, high-temperature air generated by combustion of the combustion chamber 7 is introduced into a cavity of the thermal desorption cavity 5 through a channel, the cavity is used for storing the high-temperature air, the whole thermal desorption cavity 5 is heated to a target temperature (up to 580 ℃) by utilizing heat conduction of metal for thermal desorption, organic polluted soil is pushed to move forwards in the thermal desorption cavity 5 by a spiral rod 6 in the thermal desorption process, the retention time of the polluted soil is determined by the rotating speed of the rotary drill 6 and is generally 20-40 minutes, a baffle is arranged on the rotary drill 6 to help to push the soil in the pipe body, direct contact between the soil and flame is avoided, and the heat generated by heating can be fully utilized; the induced draft fan makes the interior negative pressure that produces of thermal desorption chamber 5, extracts the waste gas that thermal desorption produced in thermal desorption chamber 5 and gets into combustion chamber 7 and burn, and the hot gas after the burning gets into in the cavity 5.2 of thermal desorption chamber 5 through passageway 36, circulates in proper order, realizes going on when thermal desorption and the waste gas secondary firing that thermal desorption produced.
The wall body of the combustion chamber 7 comprises an inner wall 33 and an outer wall 32, an interlayer is arranged between the inner wall 33 and the outer wall 32, a plurality of small holes 31 with the diameter of 30mm are arranged on the inner wall 33, and the interlayer is communicated with a channel 36; waste gas that the thermal desorption produced and the steam that soil body heat exchange unit 28 produced get into the combustion chamber after the effect of centrifugal force dust particle will go into the intermediate layer between inner wall and the outer wall through the aperture 31 of inner wall, the dust of the relative great granule of preliminary elimination alleviates the wearing and tearing of device, increases follow-up dust collection efficiency simultaneously.
The two burners of the combustion chamber 7 of the thermal desorption system are respectively a burner I29 and a burner II 30, the two burners are arranged diagonally, and under the guidance of hot air flows sprayed by the burners I29 and the burners II 30 which are arranged diagonally, an anticlockwise rotating air flow can be formed in the combustion chamber 7, so that the contact area between the organic polluted gas and flame is increased, the organic polluted waste gas is fully contacted with hot air, the full decomposition of the organic polluted waste gas is promoted, and the efficiency of the device is improved;
the number of the channels 36 is two, namely a gas channel I34 and a gas channel II 35, the gas channel I34 and the gas channel II 35 are symmetrically arranged, and high-temperature air combusted in the combustion chamber 7 enters the thermal desorption cavity 5 through the two channels 36, so that efficient utilization of energy is realized;
one for each burner 36.
The inner wall of the cavity 5.2 is made of high-temperature-resistant heat conduction materials, the outer wall of the cavity is made of high-temperature-resistant heat insulation materials, and a layer of ceramic fiber heat insulation materials is coated outside the outer wall of the cavity.
The heat recovery system is characterized in that an air blower I23 and an air blower II 24 are arranged on the soil body heat exchange unit 28, a feeding port 22 and a cooled soil outlet 27 are arranged at the top of the soil body heat exchange unit 28, the feeding port 22 is connected with the soil material outlet 10 of the heat desorption cavity, the cooled soil outlet 27 is connected with a belt conveyor for cooling and discharging soil (used for conveying cooled soil bodies to the outside of the soil body heat exchange unit), the bottom of the soil body heat exchange unit 28 is connected with a soil body heat exchange unit exhaust pipe 26, the soil body heat exchange unit exhaust pipe 26 is connected with a waste heat recovery hot air inlet 9, and an induced draft fan 25 is arranged on the soil body heat exchange unit exhaust pipe 26; the soil body heat exchange unit 28 is used for cooling the high-temperature soil and introducing the hot gas exhausted by the high-temperature soil into the combustion chamber for utilizing the waste heat.
When high temperature polluted soil enters from the feeding port 22 above the soil body heat exchange unit 28, the air blower I23 and the air blower II 24 are opened to enable cold air to be fully contacted with the high temperature soil, the soil temperature is effectively reduced, after the cold air is fully contacted with the soil body, a large amount of heat is transferred to the cold air from the soil body, the air with a large amount of heat is guided to the combustion chamber 7 through the soil body heat exchange unit exhaust pipe 26 by the induced draft fan 25, fuel and heat are provided for the combustor, the waste heat of the soil after the high temperature desorption is fully utilized, and the energy conservation and the environmental protection are realized.
The tail gas purification system mainly purifies incineration flue gas, and has the main tasks of removing fly ash particles as far as possible, decomposing and adsorbing toxic gases such as dioxin and the like, and removing HCL and SOX、NOXWaiting for inorganic gas to enable various concentration emission indexes of pollutants in the discharged flue gas to reach specified values; the tail gas purification system comprises a cyclone dust collector 14, a bag-type dust collector 15, a spray cooling tower 18 and an active carbon adsorption device 20 which are connected in sequence;
the top of the cyclone dust collector 14 is provided with an air inlet pipe 11 and an air outlet pipe 12, the bottom of the cyclone dust collector is provided with an ash bucket 13, and the outlet end of the ash bucket 13 is provided with a star-shaped blanking valve;
the bag-type dust collector 15 is provided with a bag-type dust collector flue gas inlet 16 and a bag-type dust collector flue gas outlet 17;
the activated carbon adsorption device 20 is provided with an activated carbon adsorption device flue gas inlet 19 and an activated carbon adsorption device flue gas outlet 21, the activated carbon adsorption device flue gas outlet 21 is provided with a centrifugal fan 39, the activated carbon adsorption device 20 comprises 2 activated carbon tanks used in parallel, and honeycomb-shaped activated carbon for carrying out thin film flowering in 9m is required to be placed in each activated carbon tank, and the thin film flowering method is 18m in total; the activated carbon is invalid after about 90 days of use, needs to be replaced by new activated carbon, and the waste activated carbon belongs to dangerous waste and is sent to enterprises with dangerous waste disposal qualifications for final disposal.
An air inlet pipe 11 of the cyclone dust collector 14 is connected with a combustion chamber flue gas outlet 8 of the combustion chamber 7, an air outlet pipe 12 is connected with a bag-type dust collector flue gas inlet 16, and a bag-type dust collector flue gas outlet 17 is connected with an activated carbon adsorption device flue gas inlet 19 through a spray cooling tower 18;
the cyclone 14 separates dust particles from the airflow under the action of centrifugal force, and the dust particles fall into the dust hopper 13 under the action of gravity; then further removing fine dust particles by a bag-type dust collector 15; the tail gas after dust removal enters a spray cooling tower 18, so that the temperature is reduced to normal temperature, the residual pollutants are discharged into a sewage treatment tank in a liquid state for centralized treatment, and meanwhile, the service life of the activated carbon adsorption device can be greatly prolonged; the residual tail gas after cooling is discharged after the tail gas passes through the activated carbon adsorption device 20 and the VOC monitoring system displays that the tail gas reaches the standard, and the activated carbon adsorption device 20 is mainly used for adsorbing some low-boiling heavy metals such as lead, mercury and the like evaporated in a thermal desorption link and is generally difficult to remove in dust removal and toxic and harmful gas removal. Because the output of the tail gas is very small compared with the amount of the flue gas generated by fuel combustion, harmlessness is realized through high-temperature incineration, and the reduction of the tail gas is realized through condensation and activated carbon adsorption, and the measures can ensure the standard emission of the flue gas.
The outlet end of the spray cooling tower 18 is connected with a wastewater treatment system in the plant, and the wastewater treatment system adopts a Fenton reactor (namely, the outlet water of the regulating reservoir is lifted by a pump and flows into the Fenton reactor, and H is respectively added into the Fenton reactor2O2And FeSO4, H2O2And Fe2+The hydroxyl radical with extremely strong oxidizability is generated by reaction in the environment with PH =3, and macromolecular organic matters can be oxidized into micromolecular organic matters to be further converted into carbon dioxide and water, so that pollutants which are difficult to degrade in waste water are oxidized and degraded. In order to prevent incomplete reaction of the Fenton oxidation unit, an activated carbon adsorption unit is added behind the Fenton unit so as to prevent pollutants such as polycyclic aromatic hydrocarbon and the like from being leaked due to incomplete removal after Fenton oxidation and ensure that the finally-up-to-standard water is discharged after sewage treatment. Sludge generated in the wastewater treatment process firstly undergoes drying treatment and then enters the ectopic indirect thermal desorption equipment again for treatment), and sludge generated in the wastewater treatment process undergoes drying treatment and then enters the ectopic indirect thermal desorption equipment again for treatment.
The tail part of a thermal desorption cavity 5 of the thermal desorption system is provided with a temperature sensor and a pressure sensor, and the temperature and the pressure in the cavity are monitored in real time. Organic polluted waste gas in the thermal desorption cavity and air with waste heat in the soil heat exchange unit are continuously flushed into the combustion chamber; the top of the combustion chamber 7 is provided with a temperature sensor and a pressure sensor, so that the pressure and the temperature in the combustion chamber are ensured to be within a safe range, and the organic pollution waste gas in the combustion chamber can be fully burnt under the guidance of air flow formed by the diagonally arranged combustors.
A thermal desorption process for organic polluted soil, wherein the organic polluted soil is subjected to indirect thermal desorption in a thermal desorption system, the organic polluted soil in the thermal desorption system is heated under the condition of not contacting high-temperature gas by utilizing the heat conduction of metal in the indirect thermal desorption process to carry out thermal desorption, the waste generated by the thermal desorption is subjected to secondary burning while the thermal desorption is carried out, then the dust particles generated by burning are subjected to primary dust removal treatment by utilizing reverse airflow formed by burners arranged in diagonal angles (the organic polluted soil passing through a metering feeding system enters a thermal desorption cavity 5 through a thermal desorption cavity soil material inlet 4 in the thermal desorption cavity 5, a burner I29 and a burner II 30 are opened before the thermal desorption, the burner generates heat to heat air by heating weather, and the thermal desorption cavity reaches a specified temperature (the temperature is set according to the boiling point of the organic pollutants in the polluted soil) through the heat transfer of the metal, feeding is started after the temperature sensor displays that the temperature reaches a specified temperature, a rotary drill (6) in the thermal desorption cavity 5 pushes polluted soil to move forwards, an induced draft fan is started at the same time, the induced draft fan guides desorbed gas containing organic pollutants to enter a combustion chamber 7 for secondary ignition, and hot gas generated by the secondary ignition enters the thermal desorption cavity 5 to provide heat for thermal desorption through heat exchange; the soil body after thermal desorption is directly discharged after being cooled by the soil body heat exchange unit, and waste heat generated in the heat exchange process of the soil body heat exchange unit is recycled into the thermal desorption system to provide fuel and heat for the thermal desorption system, so that high-efficiency utilization of heat is realized (when high-temperature soil after thermal desorption treatment enters the soil body heat exchange unit 28 through the soil material outlet 10 of the thermal desorption cavity, the air blower I23 and the air blower II 24 are opened to ensure that cold air is fully contacted with the high-temperature soil, so that the temperature of the soil can be effectively reduced, after the cold air is fully contacted with the soil, a large amount of heat in the soil is transferred into the air, the air with a large amount of heat is sent into the combustion chamber 7 of the thermal desorption system through the exhaust pipe 26 of the soil body heat exchange unit by using the induced draft fan 25, fuel and heat are provided for the combustion chamber 7, so that the waste heat of the soil after high-temperature desorption is fully utilized); and finally, further dedusting, cooling and adsorbing the flue gas subjected to thermal desorption.
Before carrying out thermal desorption to organic contaminated soil, carry out the preliminary treatment to it, adjust soil moisture through the preliminary treatment, the granule particle diameter of control soil is to suitable size for the particle diameter and the moisture content of control soil granule ensure thermal desorption efficiency, guarantee the soil moisture content of feeding and be less than 20% for the treatment effeciency of guaranteeing thermal desorption simultaneously. The physicochemical properties of the soil have certain influence on the heterotopic thermal desorption treatment process and results, and the organic polluted soil needs to be pretreated before heat treatment in consideration of the factors of high efficiency and low energy consumption. The soil moisture is adjusted, the particle size of the soil is controlled to a proper size, the reaction area and the mixing degree of the contaminated soil are increased, the soil moisture content of the fed material is lower than 20%, and the thermal desorption treatment efficiency is ensured. Digging the on-site organic contaminated soil by using an excavator, transporting the soil to a pretreatment area by using a transport vehicle, picking out large stones (D is more than or equal to 2 cm) in the soil, and screening and crushingThe device is to the great particle diameter stone in the soil, and soil screening is broken, prevents to heat the pan feeding mouth and blocks up, and the screening breaker that reuses prevents to heat the pan feeding mouth and blocks up to great particle diameter stone in the soil, soil screening, when protecting follow-up process equipment, increases soil heating effect. Returning the soil with the grain diameter larger than 2cm to the grinding and sieving machine for continuous grinding. And (4) stacking the screened soil in a temporary storage yard (the stacking yard is required to be completely closed), spreading and airing the polluted soil, wherein the stacking thickness of the aired polluted soil is 0.2 m. In order to ensure the pretreatment effect and increase the air permeability of the soil, when the soil is overturned, the water content is properly adjusted, the average particle size distribution of the pretreated soil is ensured, the water content is reduced to about 20 percent, and the requirement of ectopic indirect thermal desorption treatment on feeding is met. The operations are all carried out in a closed greenhouse. The main body frame and the outer sunshade frame of the closed greenhouse adopt hot galvanizing steel structures, and the ground of the greenhouse is impervious by adopting HDPE films with the thickness of 2.0mm and 4800 g/m of bentonite2Waterproof cloth (GCL) and laying 800 g/m2And (4) geotextile. And 3, three thousandth bidirectional slope finding in the north-south direction of the greenhouse is realized, and external drainage is adopted. 1400mm concrete short walls are arranged around the greenhouse, and an independent foundation is arranged inside the greenhouse. Two vent about airtight big-arch shelter sets up, guarantees the interior air of big-arch shelter and fully replaces through extracting upper air and lower floor's air respectively, guarantees construction worker health and safety. The main body frame and the outer sunshade framework of the closed greenhouse are made of hot galvanizing steel structures. The airtight greenhouse is provided with an upper ventilation opening and a lower ventilation opening, and the air in the greenhouse is fully replaced by respectively extracting the air of the upper layer and the air of the lower layer.
Measurement charge-in system is used for delivering to thermal desorption system with the soil after the preliminary treatment and carries out thermal desorption processing, measurement charge-in system includes hopper 1, belt weigher 3 and feeding band conveyer 2, the contaminated soil after the preliminary treatment passes through the screening machine in proper order, the breaker, the shale shaker sieves, crushing treatment, then add to hopper 1 and evenly carry to band conveyer after 3 measurement of belt weigher, the band conveyer 2 of rethread slope carries contaminated soil to the top of thermal desorption chamber soil material entry 4 in order to reach the purpose of even feeding.
In the thermal desorption process, compressed natural gas is used as fuel supply, and fuel supply units such as a compressed natural gas tank truck, a pressure reducing device, a natural gas conveying pipeline and the like are arranged on site.
The whole set of system is operated by adopting a computer automatic control system, and the required operators are few. When any part in the system has a fault, the system automatically stops, and informs an operator of the fault position through a networked computer system, so that the fault can be removed at the highest speed.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. The utility model provides an organic contaminated soil thermal desorption device which characterized in that: comprises a thermal desorption system for reducing energy consumption in the thermal desorption process, a metering and feeding system, a soil body heat exchange unit (28) and a tail gas purification system;
the thermal desorption system comprises a thermal desorption cavity (5) and a combustion chamber (7), a channel (36) for connecting the thermal desorption cavity (5) and the combustion chamber (7) is arranged between the thermal desorption cavity and the combustion chamber, and the thermal desorption system simultaneously carries out thermal desorption of the organic polluted soil and secondary burning of waste generated by thermal desorption;
be equipped with thermal desorption chamber soil material entry (4) on the thermal desorption system, thermal desorption chamber soil material export (10) and combustion chamber exhanst gas outlet (8), thermal desorption chamber soil material entry (4) link to each other with measurement charge-in system, thermal desorption chamber soil material export (10) link to each other with soil body heat transfer unit (28), the hot-air that soil body heat transfer unit (28) produced lets in combustion chamber (7), soil body heat transfer unit (28) provide fuel and heat for thermal desorption system when to the soil body cooling after the thermal desorption, thermal desorption chamber soil material entry (4) link to each other with the tail gas clean-up system to the tail gas clean-up processing that thermal desorption produced.
2. The thermal desorption device for the organic contaminated soil according to claim 1, wherein: the thermal desorption system is characterized in that a thermal desorption cavity (5) of the thermal desorption system is of a cylindrical structure, an inner cavity (5.1) is arranged inside the thermal desorption cavity (5), an auger (6) is arranged inside the inner cavity (5.1), a thermal desorption cavity soil outlet (10) communicated with the inner cavity (5.1) and a thermal desorption cavity gas outlet (38) communicated with the inner cavity (5.1) are formed in the thermal desorption cavity (5), the thermal desorption cavity soil outlet (10) is communicated with the soil heat exchange unit (28), a cavity (5.2) used for hot air circulation is formed in the wall body of the thermal desorption cavity (5), the cavity (5.2) is isolated from the inner cavity (5.1), and a dust exhaust port (41) communicated to the outside and used for exhausting dust particles out of the cavity (5.2) is formed in the cavity (5.2);
be equipped with the combustor on combustion chamber (7), passageway (36) and organic pollution waste gas entry (37) have been seted up to the bottom of combustor, passageway (36) communicate combustion chamber (7) and cavity (5.2), organic pollution waste gas entry (37) are through the pipeline intercommunication with heat desorption chamber gas outlet (38), be equipped with the draught fan on the pipeline, combustion chamber (7) still are equipped with combustion chamber exhanst gas outlet (8) and waste heat recovery hot air entry (9), combustion chamber exhanst gas outlet (8) and tail gas clean system intercommunication, waste heat recovery hot air entry (9) and soil body heat transfer unit (28) intercommunication.
3. The thermal desorption device for the organic contaminated soil according to claim 2, wherein: the wall body of combustion chamber (7) includes inner wall (33) and outer wall (32), is equipped with the intermediate layer between inner wall (33) and outer wall (32), is equipped with a plurality of aperture (31) on inner wall (33), intermediate layer and passageway (36) intercommunication.
4. The thermal desorption device for the organic contaminated soil according to claim 3, wherein: the number of the burners of the combustion chamber (7) of the thermal desorption system is two, namely a burner I (29) and a burner II (30), and the two burners are arranged diagonally;
the number of the channels (36) is two, namely a gas channel I (34) and a gas channel II (35);
one for each burner (36).
5. The thermal desorption device for the organic contaminated soil according to claim 4, wherein: the inner wall of the cavity (5.2) is made of high-temperature-resistant heat conduction materials, and the outer wall of the cavity is made of high-temperature-resistant heat insulation materials.
6. The thermal desorption device for the organic contaminated soil according to claim 5, wherein: be equipped with air-blower I (23) and air-blower II (24) on soil body heat transfer unit (28), the top of soil body heat transfer unit (28) is equipped with pan feeding mouth (22) and refrigerated soil export (27), pan feeding mouth (22) link to each other with heat desorption chamber soil material export (10), refrigerated soil export (27) are connected with the band conveyer who is used for cooling out the soil and link to each other, the bottom of soil body heat transfer unit (28) is connected with soil body heat transfer unit blast pipe (26), soil body heat transfer unit blast pipe (26) link to each other with waste heat recovery hot air entry (9), be equipped with draught fan (25) on soil body heat transfer unit blast pipe (26).
7. The thermal desorption device for the organic contaminated soil according to claim 6, wherein: the tail gas purification system comprises a cyclone dust collector (14), a bag-type dust collector (15), a spray cooling tower (18) and an active carbon adsorption device (20) which are connected in sequence;
the top of the cyclone dust collector (14) is provided with an air inlet pipe (11) and an air outlet pipe (12), the bottom of the cyclone dust collector is provided with an ash bucket (13), and the outlet end of the ash bucket (13) is provided with a star-shaped discharging valve;
a bag-type dust collector flue gas inlet (16) and a bag-type dust collector flue gas outlet (17) are formed in the bag-type dust collector (15);
the activated carbon adsorption device (20) is provided with an activated carbon adsorption device flue gas inlet (19) and an activated carbon adsorption device flue gas outlet (21), and the activated carbon adsorption device flue gas outlet (21) is provided with a centrifugal fan (39);
an air inlet pipe (11) of the cyclone dust collector (14) is connected with a combustion chamber flue gas outlet (8) of the combustion chamber (7), an exhaust pipe (12) is connected with a bag-type dust collector flue gas inlet (16), and a bag-type dust collector flue gas outlet (17) is connected with an activated carbon adsorption device flue gas inlet (19) through a spray cooling tower (18).
8. The thermal desorption device for the organic contaminated soil according to claim 7, wherein: the tail part of a thermal desorption cavity (5) of the thermal desorption system is provided with a temperature sensor and a pressure sensor; the top of the combustion chamber (7) is provided with a temperature sensor and a pressure sensor.
9. The thermal desorption process carried out by the thermal desorption device for the organic contaminated soil according to claim 1, which is characterized in that: carrying out indirect thermal desorption on the organic polluted soil in a thermal desorption system, carrying out thermal desorption on the organic polluted soil in the thermal desorption system under the condition that the organic polluted soil is not contacted with high-temperature gas by utilizing the heat conduction of metal in the indirect thermal desorption process, carrying out secondary firing on waste generated by thermal desorption during the thermal desorption, and carrying out primary dust removal treatment on dust particles generated by firing by utilizing airflow formed by burners arranged in an oblique diagonal manner; the soil body after thermal desorption is directly discharged after being cooled by the soil body heat exchange unit, and waste heat generated in the heat exchange process of the soil body heat exchange unit is recycled into the thermal desorption system, so that fuel and heat are provided for the thermal desorption system, and high-efficiency utilization of the heat is realized; and finally, further dedusting, cooling and adsorbing the flue gas subjected to thermal desorption.
10. The thermal desorption process of the organic contaminated soil according to claim 9, wherein: before the organic contaminated soil is subjected to thermal desorption, the organic contaminated soil is pretreated, the soil moisture is adjusted through the pretreatment, and the particle size of the soil is controlled to be a proper size.
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| CN202110532302.3A CN113319113A (en) | 2021-05-17 | 2021-05-17 | Thermal desorption device and process for organic contaminated soil |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114522972A (en) * | 2022-03-08 | 2022-05-24 | 广东工业大学 | Soil thermal desorption fluidized bed adjusting system and adjusting method |
| CN114833186A (en) * | 2022-03-29 | 2022-08-02 | 浙江工贸职业技术学院 | Thermal desorption combined combustion treatment method for soil organic pollutants |
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2021
- 2021-05-17 CN CN202110532302.3A patent/CN113319113A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114522972A (en) * | 2022-03-08 | 2022-05-24 | 广东工业大学 | Soil thermal desorption fluidized bed adjusting system and adjusting method |
| CN114833186A (en) * | 2022-03-29 | 2022-08-02 | 浙江工贸职业技术学院 | Thermal desorption combined combustion treatment method for soil organic pollutants |
| CN114833186B (en) * | 2022-03-29 | 2023-08-11 | 浙江工贸职业技术学院 | Thermal desorption combined combustion treatment method for soil organic pollutants |
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